1. Field of the Invention
The invention relates to a cathode ray tube with a deflection unit comprising a saddle-shaped deflection coil with a flange, said deflection coil flaring out in a fan-shaped manner from a rear end to a front end.
The invention also relates to a deflection unit for a cathode ray tube.
The invention further relates to a method of manufacturing a saddle-shaped deflection coil of a deflection unit for a cathode ray tube.
2. Description of the Related Art
Cathode ray tubes of the type mentioned in the opening paragraph are well-known and are used, inter alia, for and in television receivers and computer monitors.
Customarily, a set of saddle-shaped line deflection coils and a set of saddle-shaped frame deflection coils or a set of frame deflection coils which are toroidally wound on a core, are combined into an electromagnetic deflection unit. The nominal design of the coils may be such that, for example, specific requirements relating to the geometry of a raster scanned by means of the deflection unit on the display screen of a display tribe and/or requirements relating to the convergence of the electron beams on the display screen are met. The coils are wound on a winding machine and include current-supply wires and a beginning of these current-supply wires. The current-supply wires are wound in a winding machine so as to obtain the shape of a coil, and are subsequently baked, in which baking process the current-supply wires are bonded together. The aim is to reduce the time necessary to manufacture a coil and/or to reduce rejects.
To achieve this, the deflection coil in accordance with the invention is characterized in that the beginning of the current-supply wires is largely detached from the flange, which flange does not exhibit an impression of the beginning of the current-supply wires at the location where said beginning is detached from the flange.
Conventional coils have current-supply wires whose beginning, in the manufacturing process, lies against the flange and is adhered to the flange. However, this has the disadvantage that, in operation, the beginning of the current-supply wires is in the vicinity of current-supply wires which are at a much higher or much lower voltage. This may cause flashover. To preclude this, said beginning is largely pulled loose from the flange after the manufacture of the coil. However, in conventional coils said beginning has left an impression in the flange, which adversely affects the fields generated by the coil. In the cathode ray tube in accordance with the invention, this impression is absent, which causes the quality to be improved and, in particular, reduces the spread in quality. It is also important that the beginning is no longer pulled loose, so that the risk of damage to the insulation layers on current-supply wires, and hence the risk of rejects, is reduced. In addition, the deflection unit can be manufactured more rapidly, resulting in a saving of costs.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.